Structurally supported lcd media

ABSTRACT

A structurally supported LCD media comprising: an initial structural layer; a plurality of addressable layers, each of which having predetermined optical properties, and the layers have LC there-between and have narrow conductive pathways on opposing faces which respectively address a predetermined LC volume between the pathways, and the pathways are respectively accessible for interconnection with a LC electric pulse driving means; a final structural layer being of predetermined optically transparency to frequencies of light scattered by at least one of the other layers; and means for sealing the initial layer to the final layer with the addressable layers there-between.

A portion of the disclosure of this patent document contains materialthat is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in the Patent and TrademarkOffice patent file or records, but otherwise reserves all copyrightrights whatsoever.

Field of the Invention

The present invention generally relates to low cost Liquid CrystalDisplays (LCDs).

More specifically, the present invention relates to a compositematerials approach to fabrication of LCDs.

BACKGROUND OF THE INVENTION

LCDs are typically fabricated using parallel pairs of structurally rigid& precision flat sheet glass having an addressable conductive pattern onrespective facing surfaces and having a liquid crystal based materialthere-between. Glass is presently the preferred media because of itsoptical properties, its structural properties, its chemical properties(being impermeable to moisture and oxygen) and because it facility toedge sealing or interstitial sealing. Furthermore, in order to maintainthe parallel orientation, precision spacers (e.g. micro spheres) aredistributed between the plates, albeit obscure fabrication methodsutilize precise deposition to accomplish the spacing.

Because the cost of structurally rigid & precision flat sheet glassincreases greatly with the size of the sheets, large and very large LCDsare disproportionably more expensive than hand held displays or watchface size displays.

Accordingly, there is a long felt need in the industry to reduced thecost of large and very large LCDs. Furthermore, additional costreductions for hand held displays or watch face size displays would alsobe appreciated as advantageous to the industry, since manufacture ofsmall scale LCDs has become highly competitive.

BRIEF SUMMARY OF THE INVENTION

The aforesaid longstanding needs are significantly addressed byembodiments of the present invention, which specifically relates tostructurally supported LCD media. The instant apparatus is especiallyuseful in lowering costs for LCD fabrication.

The instant invention specifically relates to embodiments of aStructurally supported LCD media comprising: (A) a initial structurallayer; (B) a plurality of addressable layers, each of which havingpredetermined optical properties, and the layers have LC there-betweenand have narrow conductive pathways on opposing faces which respectivelyaddress a predetermined LC volume between the pathways, and the pathwaysare respectively accessible for interconnection with a LC electric pulsedriving means; (C) a final structural layer being of predeterminedoptically transparency to frequencies of light scattered and/orreflected by at least one of the other layers; and (D) means for sealingthe initial layer to the final layer with the addressable layersthere-between, and having there-through a continuation of saidrespective accessible interconnection.

Simply stated, embodiments of the instant invention facilitate use ofcheap plastic sheet to be used roll-to-roll and thereafter cut up andlaminated with cheap glass. This allows large area cheap LC displays byenclosure of a stack of films into a “sandwich”.

According to one embodiment, the initial structural layer is a rigidmaterial (e.g. glass, composite, metal, or the likes) having an inertsurface (innately, by coating, by preparation, or the likes) facing thefinal layer. According to the a special variation of this embodiment,the inert surface is an applied coating/deposition on the surface.

According to a special embodiment, the initial structural layer isglass. While according to a further embodiment, the initial structurallayer is selected from the list: metal, plastic, and composite material.

According to a different embodiment, the initial structural layer has asurface preparation of predetermined spectral properties (generallyoptically black—but often tinted, textured, selectively filtered, or thelikes) facing the final layer.

According to yet another embodiment, at least one of the plurality ofaddressable layers is made from a plastic film. However, according tostill a further embodiment, at least one of the plurality of addressablelayers is made from a glassy film. While according to an additionalembodiment, at least one of the plurality of addressable layers is madefrom a plastic sheet.

According to a novel embodiment, the narrow conductive pathways areselected from the list: Indium Tin Oxide, carbon nanotubes, or thelikes. According to another novel embodiment, at least two adjacentlayers of the plurality of addressable layers are separated by precisionwidth gaping spacers selected from the list: micro-particles, depositionmembers, at least one mesh, a randomized network layer, a latticestructured network layer, a highly perforated membrane or the likes.

According to a further novel embodiment, the final structural layer is aglass sheet.

According to still a further fundamental embodiment, the initialstructural layer and the plurality of addressable layers and the finalstructural layer in combination provide a predetermined measure ofrigidity that is compliant with a predetermined measure of integrity forthe initial layer to final layer sealing.

Essentially, this means that the entire structurally supported LCD mediamight be bent or flexed so long as that does not disrupt the sealingbetween the initial and final layer. More particularly, according to thepreferred variation of this embodiment, at least two adjacent layers ofthe plurality of addressable layers are separated by precision widthgaping spacers selected from the list: micro-particles, depositionmembers, mesh, randomized network layer, lattice structured networklayer, and highly perforated membrane; and wherein the predeterminedmeasure of rigidity also includes the structural contribution of theprecision width gaping spacers. Thus, as the initial structural layer oras the final structural layer (and incidently as any of the addressablelayers) a barier multi-layer laminate “film” may be included thatstatistically preventing oxygen or moisture percolation—due to the grossimprobability of aligned defects between layers of the laminate. Forexample using PET film alternated with silicon dioxide or aluminum oxideand/or organic intermediate layers result in clear or opaquemicro-laminates.

A commercial product by Vitex (called Barix-tm) fulfills this functionalspecification. “The bulk permeability of even a thin inorganic layer ofsilicon dioxide (glass) or aluminum oxide (ceramic) is essentiallyzero—they are perfect barriers. So why does a coating of these materialson a plastic film allow the passage of water or oxygen? The reason isthat to produce an impermeable barrier, such a coating must becontinuous and free of any defects. However, when applied to a plasticsurface, these coatings perform as though they are riddled with holes.Microscopic inspection shows why: the surface of the plastic is notsmooth. On a molecular scale, it is a landscape of mountains andvalleys. Each mountain peak and valley bottom creates a moisture pathknown as a grain boundary defect. Increasing the thickness of theinorganic layer does not solve the problem. The point and line defectsgrow right along with the thickness of the film, so that cracks andholes go clear through the inorganic layer, allowing moisture topenetrate and damage the display. Vitex's VPT technology proposed tosolve this dilemma.” However, other simpler laminates are alsosubstantially sufficient in the context of the instant invention.Alternatively, the LC materialsl may be encapsulated into addressablemicro-cells, which are respectively held in relative position by theinitial and final structural layers.

According to a basic embodiment, the structurally supported LCD media(substantially as herein described and illustrated) is characterized byhaving means for (moisture & oxygen impermeable) sealing the initiallayer to the final layer. Essentially this takes the form of two basicembodiments. Firstly, an embodiment whereby the initial and finalstructural layers collectively with the sealing means provide theisolation of the LC from environmental moisture and oxygen. Secondly, anembodiment whereby micro-cells of LC in the interstitial regions arestructurally maintained in respective position by the initial and finalstructural layers and the sealing means—albeit the environmentalisolation is provided by the micro-cell encapsulation or by thelamination of interstitial layers (in conjunction with gaping spacerstructure).

Plastic LCD in a glass sandwich. In the future it is possible that LCD'scould be made on a roll to roll basis and thus make them very cheap.Cheap plastic substrates have poor barrier properties to water andoxygen. ‘Engineered’ plastic film with barrier layers is very expensive.This idea takes cheap plastic and encloses it between thin glass sheetsthat act as barrier layers and can be also helpful in making the devicemore rigid when this is required.

Notices

Numbers, alphabetic characters, and roman symbols are designated in thefollowing sections for convenience of explanations only, and should byno means be regarded as imposing particular order on any method steps.Likewise, the present invention will forthwith be described with acertain degree of particularity, however those versed in the art willreadily appreciate that various modifications and alterations may be,carried out without departing from either the spirit or scope, ashereinafter claimed.

In describing the present invention, explanations are presented in lightof currently accepted Scientific or Technological theories and models.Such theories and models are subject to changes, both adiabatic andradical. Often these changes occur because representations forfundamental component elements are innovated, because newtransformations between these elements are conceived, or because newinterpretations arise for these elements or for their transformations.Therefore, it is important to note that the present invention relates tospecific technological actualization in embodiments. Accordingly, theoryor model dependent explanations herein, related to these embodiments,are presented for the purpose of teaching, the current man of the art orthe current team of the art, how these embodiments may be substantiallyrealized in practice. Alternative or equivalent explanations for theseembodiments may neither deny nor alter their realization.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to understand the invention and to see how it may be carriedout in practice, embodiments including the preferred embodiment will nowbe described, by way of non-limiting example only, with reference to theaccompanying drawings. Furthermore, a more complete understanding of thepresent invention and the advantages thereof may be acquired byreferring to the following description in consideration of theaccompanying drawings, in which like reference numbers indicate likefeatures and wherein:

FIG. 1 illustrates a schematic lateral side view of a structuralsupported LCD media embodiment; and

FIG. 2 illustrates a schematic view of sequential steps used to assemblea typical structural supported LCD media embodiment.

DETAILED DESCRIPTION OF THE INVENTION

The instant invention relates to embodiments (SEE FIG. 1) of aStructurally supported LCD media comprising: (A) a initial structurallayer 100; (B) a plurality of addressable layers, each of which havingpredetermined optical properties 110 120 130, and the layers have LC 111121 there-between and have narrow conductive pathways 112 122 123 133 onopposing faces which respectively address a predetermined LC volumebetween the pathways, and the pathways are respectively accessible forinterconnection with a LC electric pulse driving means; (C) a finalstructural layer 140 being of predetermined optically transparency tofrequencies of light scattered and/or reflected by at least one of theother layers; and (D) means for sealing 150 the initial layer to thefinal layer with the addressable layers there-between, and havingthere-through a continuation of said respective accessibleinterconnection.

Regarding the means for sealing, one needs a specification for water andoxygen transport through a substrate into a liquid crystal film that isvery low [while PET (Polyethylene terephthalate) for example has veryhigh transport properties: Water Oxygen (g/m²/day) (cc/bar/m²/day)Target <10⁻² <10⁻² PET film (1 mil)  40 160

Glass (by comparison) has almost zero permeation of water and oxygen.

It is possible to obtain from Agfa a laminate of glass and plastic thatis 450 um thick which is flexible. It is sold as a substrate fordisplays and security cards, semiconductor devices etc. (seehttp:/www.yet2.com/nasatech/240). It is patented for used in LCD's.

Schott and others sell very thin glass of 50 um thick, this is expensiveand while flexible is also brittle. Borosilicate glass is less breakablethan sodium or chemically hardened glass so is preferred in theseapplications.

The disadvantage of using this thin glass is that it comes in sheets notrolls so roll to roll manufacture is not an option. The plastic/glasslaminate is possibly a roll although this is not emphasized strongly inthe technical notes.

In preferred instant embodiments of the present invention, the LCD ismade by coatings onto cheap transparent conductive-coated cheap plasticand then sandwiched between cheap soda lime glass in sheets of theappropriate size defined by the application and ability to drive theLCD.

The edges of the glass are sealed thus creating an almost hermetic sealfor the plastic. (SEE FIG. 2) On the bottom of a Structurally supportedLCD media 200 is a initial structural layer 210 supports a stack of: aplastic layer 220, a first coated SCT layer cured to give a PDLC likefilm 230, a second coated film 240, a third coated SCT film 250, and anupper laminated plastic 260. A final structural layer 270 is beingdeposits on top of the stack; then there is lamination from the initialstructural layer to the final structural layer by a means for sealing280—with the addressable layers there-between.

Alternatively making individual layers and then stacking these prior tolamination between glasses can make the stack of SCT layers.

Special care should be taken to avoid problems of large mismatch inexpansion between glass and plastic but using suitable glues (indeedAgfa have shown this can be done).

Furthermore, it is preferred to limit added weight and loose flexibilityof the plastic display. The weight depends on the glass thickness—0.8 mmglass could be used as the plastic will make it tougher. Flexibility isnot a big deal, usually ruggedness is more critical and this sandwichwould be rugged.

Care should be taken not to include extra steps in lamination—since thiswill add cost. Furthermore, connection to the device via flexibleprinted circuits or rigid connectors requires careful selection and mayincur a need to electrically connect between plastic and glass.

Briefly, instant embodiments use comparatively cheap substrates(especially for large surface area displays)—and can utilizeroll-to-roll manufacture (since the very weak point of plastic devicesmade roll to roll is to seal the edges, this is overcome). In addition,substantially any device size is possible—and one could attach driverson the glass (if desired).

Simply stated, instant embodiments use a good and cheap barrier layer(glass) to overcome the barrier layer problem in cheap non-engineeredplastics. (Note that the engineering of plastics is usually silicondioxide layers evaporated onto the plastic.)

While the invention has been described with respect to specific examplesincluding presently preferred modes of carrying out the invention, thoseskilled in the art will appreciate that there are numerous variationsand permutations of the above described systems and techniques that fallwithin the spirit and scope of the invention as set forth in theappended claims.

I/We claim:
 1. Structurally supported LCD media comprising: a initialstructural layer; a plurality of addressable layers, each of whichhaving predetermined optical properties, and the layers have LCthere-between and have narrow conductive pathways on opposing faceswhich respectively address a predetermined LC volume between thepathways, and the pathways are respectively accessible forinterconnection with a LC electric pulse driving means; a finalstructural layer being of predetermined optically transparency tofrequencies of light scattered and/or reflected by at least one of theother layers; and means for sealing the initial layer to the final layerwith the addressable layers there-between, and having there-through acontinuation of said respective accessible interconnection.
 2. Thestructurally supported LCD media according to claim 1 wherein theinitial structural layer is a rigid material having an inert surfacefacing the final layer.
 3. The structurally supported LCD mediaaccording to claim 2 wherein the inert surface is an appliedcoating/deposition on the surface.
 4. The structurally supported LCDmedia according to claim 1 wherein the initial structural layer isglass.
 5. The structurally supported LCD media according to claim 1wherein the initial structural layer is selected from the list: metal,plastic, and composite material.
 6. The structurally supported LCD mediaaccording to claim 1 wherein the initial structural layer has a surfacepreparation of predetermined spectral properties facing the final layer.7. The structurally supported LCD media according to claim 1 wherein atleast one of the plurality of addressable layers is made from a plasticfilm.
 8. The structurally supported LCD media according to claim 1wherein at least one of the plurality of addressable layers is made froma glassy film.
 9. The structurally supported LCD media according toclaim 1 wherein at least one of the plurality of addressable layers ismade from a plastic sheet.
 10. The structurally supported LCD mediaaccording to claim 1 wherein the narrow conductive pathways are selectedfrom the list: Indium Tin Oxide, carbon nanotubes.
 11. The structurallysupported LCD media according to claim 1 wherein at least two adjacentlayers of the plurality of addressable layers are separated by precisionwidth gaping spacers selected from the list: micro-particles, depositionmembers, at least one mesh, a randomized network layer, a latticestructured network layer, and a highly perforated membrane.
 12. Thestructurally supported LCD media according to claim 1 wherein the finalstructural layer is a glass sheet.
 13. The structurally supported LCDmedia according to claim 1 wherein the initial structural layer and theplurality of addressable layers and the final structural layer incombination provide a predetermined measure of rigidity that iscompliant with a predetermined measure of integrity for the initiallayer to final layer sealing.
 14. The structurally supported LCD mediaaccording to claim 13 wherein at least two adjacent layers of theplurality of addressable layers are separated by precision width gapingspacers selected from the list: micro-particles, deposition members,mesh, randomized network layer, lattice structured network layer, andhighly perforated membrane; and wherein the predetermined measure ofrigidity also includes the structural contribution of the precisionwidth gaping spacers.
 15. The structurally supported LCD mediasubstantially as hereinbefore described and illustrated andcharacterized by having means for sealing the initial layer to the finallayer.